Piezo-electric crystal apparatus



Oct. 25, 1932.

E. R. HENTSCHEL PIEzo ELECTRIC CRYSTAL APPARATUS Filed Aug. 16. 1929 3T Lal l Z maw, .Y. Aj Mw, mo m 0 4 2 5 .j ,1T 4 0 @d A a m WQ. 7 Q .XV u u m/w l? A@ VME l 5 E4 d 2 4 f 2 U i@ x Hvwl- HI@ .H4 IZ v 0 a MMM, ,f a f 1 AO y 2 J LI E Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE ERNEST R. HENTSCHEL, OF WASHINGTON, DISTRICT OF COLUMBIA; JOHN OLSON, AD-

MINISTRATOR 0F SAID ERNEST E. HENTSCHEL, DECEASED, ASSIGNOZR TO WIBED RADIO, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE PIEZO-ELECTRIC CRYSTAL APPARATUS Application led August 16, 1929. Serial N0. 386,440.

My invention relates broadly to piezo electric crystal apparatus and more particularly to a construction of dust proof holder for a piezo electric crystal element.

@ne of the objects of my invention is to provide a construction of piezo electric crystal apparatus wherein means are provided for mounting various sizes of piezo electric crystal elements at the same time that the casing in Which the selected piezo electric crystal element is mounted, is maintained in substantially closed condition and the crystal therein substantially protected.

Another obj ect of my invention is to provide a housing for selected sizes or' piezo electric crystal elements in which the selected piezo electric crystal element is free to vibrate with substantially no restriction and is maintained substantially closed for the protection of the crystal element therein.

@ther and further objects of my invention reside in the construction of piezo electric crystal mounting set forth in the following specification and shown in the accompanying drawing in Which:

Figure l is a plan view taken on line 1-1 of Fig. 2 illustrating the piezo electric crystal element assembled Within the piezo electric crystal holder according to the principles of my invention;

Fig. 2 is a cross sectional vieW through the piezo electric crystal holder taken on line 2 2 of Fig. l;

Fig. 3 is a plan view of a modified construction of mounting for piezo electric crystal elements or" various sizes Within a holder according to the principles of my invention;

Fig. l is a cross-sectional view taken through the modilied construction of mounting on line l-Ll of Fig. 8; and

Fig. 5 is a cross-sectional view taken through the piezo electric crystal holder of Fig. 3 on line 5-5 thereof.

I-Ieretotore in the art, housings for piezo electric crystals have been constructed which are adapted to receive piezo electric crystals of different sizes for the generation of oscillations at dilerent frequencies but these housings have had a number of disadvantages inasmuch as they have not protected the piezo electric crystal element against the entry of moisture and dust. This has been true by reason of the arrangement of permanent apertures through the bottom of the casing for the passage of textile cords therethrough, which cords have been employed for the centering of the piezo electric crystal element Within the housing. In prior crystal holders a portion of the retaining means for the piezo electric crystal has been necessarily external to the piezo electric crystal and moisture and dust seep through the apertures through which the external retaining means pass to the interior of the piezo electric crystal housing, thereby acting to the detriment of the etiicient operation of the piezo electric crystal element.

In my invention, I provide a completely closed housing Within Which the piezo electric crystal element is mounted and upon the interior of the base of this housing I mount a supporting plate which is properly drilled and apertured for the passage oi' textile cords which are so disposed around the piezo electric crystal element that the piezo electric crystal element may be centered Within the housing and maintained free to vibrate Without restriction at the same time that moisture and dust are excluded from the housing by reason oi the fact that the centering means for the crystal are located Wholly Within the housing and do not extend exterior thereof.

Referring to the drawing in detail, reference character l designates a metallic base member which protrudes upwardly at its center as indicated at la and extends interiorly in an upward direction Within the housing formed by the cylindrical Wall 22 of insulated material. The plate l carries piezo electric crystal mounting plate 2 which is secured in position upon the crowned or upwardly extending portion la of the plate l by means of screws 3. The portion la of plate 1 is diametrically grooved as indicated at 4, cooperating with a corresponding diametrical groove in the supporting plate member 2.

4rlhat is to say, a substantially semicircular groove is cut in the portion la as shown at 5, and a corresponding groove is cut in the supporting plate 2 as indicated at 6. At right angles to the grooves 5 and 6, I provide a pair of grooves 7 and 8, the groove 7 being diametrically cut in the upwardly extending portion 1a of plate 1 and the groove 1a being cut in the under surface of the supporting plate 2. The peripheral edges of the supporting plate 2 are slotted as shown at 9, 10, 11 and 12 to receive textile cords 14 and 15, enabling the cords to be stretched over the peripheral Vedges neath the supporting plate 2 for centering the piezo electric lcrystal within the housing 22. It will be clear that the textile cords 14 and lrmay embrace piezo electric crystals of different sizes, the cords stretching around the peripheral edges and being drawn taut by means of hook 25 on upper member 24, which is anchored at its extremity in the notch 23 cut in the upper portion of one side of cylindrical wall 22. The textile cords are tied at anysuitable point along the length thereof to form'loops which may be resilientlysupportedv bythe hook member 25 around the sides of any vselected piezo electric crystal' element. The top of the Contact plate 17 is connected at 18 toa flexible conductor 19 which connects to lug 2O on the protruding connection member 21 at one side of the casing. The plate 1 connects to pedestal member 34 by means of the screw 29 and the pedestal is secured at the opposite end by means of screw 28 which passes through the insulated top V26 of the housing. The pedestal 34 carries an extension member 30 which projects from the side of the casing 22 opposite tothe projection 21 and by lmeans of these oppositely disposed projections connection of the piezo electric crystal element within the mounting may be established.

The plate 1 is secured tothe insulating housing 22 at other points about its periphery asl indicated at 29a. The insulated top 26 of the housing is secured to thehousing by means of screws 28a. Vf here the size of the piezo electric crystal elements which are to be used in the piezo electric crystal holder may be predetermined, as for example by selected frequency settings, at which the piezo electric crystal apparatusis to operate several pairs of apertures may be drilled or cut through the supporting plate 2 in predetermined positions. I have shown this modified construction in Figs. 3, 4 and 5, wherein the supporting plate 33 is notched at diametrically opposite positions indicated at 32 and is apertured by means of pairs of apertures indicated at 31 for the passage of textile cords electric crystal holder. Any desired number' of aperturesl maybe provided in the plate 88 to accommodate the housing for thereception of piezo electric crystals of dierent sizes.

It will be seenthat none of the apertures or grooves penetrate the lower base 1 so that the housing in which the piezo electric crystal is located is entirely closed against the dust or moisture and the piezo elec-tric crystal element is thoroughly protected at the same time that the piezo electric element is free to vibrate without restriction. I may provide suitable gaskets between the ends of the cylindrical wall 22 and the metallic base member 1 and upper plate 26 in order to hermetically seal the piezo electric crystal holder. n

In some instances it may be necessary to extend screws 28a from the top insulated closer plateA 26 through the cylindrical wall 22 tothe base platel where the screws are soldered Aor otherwise secured for the hermetic closing of the housing.v

The'piezo electric crystal holder of my invention has been found to be highly practical in lits construction and successful in its operation and whileI have describedparticular embodiments of my invention, I desire that it be understood that modifications may be made and that-I intend no limitations upon my invention other than are imposed by the scope of the appended claim.

`What I claim as new and desire to secure by Letters Patent of the United States is as follows Piezo electric crystal apparatus comprising a base member, a. hermetically sealed insulated housing carried by said base member, a metallic supporting plate member secured to the interior of said base member within said housing, a piezo electric crystal element having one face thereof in contact with said supporting plate member, a metallic contact plate in contact with another face of said crystal, said supporting plate member having diametral grooves cut in the face thereof in'c'ontact with said base member and extending substantially normal to each other, said base member having correspondingly aligned grooves cut therein, the face of said supporting plate member in contact with said crystal being multiply .apertured near each end Vof each of said diametral grooves symmetrically with reference'to a central point of said supporting plate member, supportingmeans attached to said housing, and flexible cords supported by said supporting means and passing throughl said diametral grooves in said supporting plate and through apertures in the face thereof in Contact with said crystal symmetrically disposed with reference to a centrai point*J of said plate member and disposed t one near each end of each of said dametral 

